El Caminito del Rey (The King's little pathway) near Malaga was responsible for five deaths between 1999 and 2000 and so became dubbed 'the world's most dangerous walkway'. Thankfully it's been renovated since then and looks very tame now - so tame in fact, that you can ride a bike along it, as proven by David Cachon.

It's worth noting the path is normally closed to bikes but it still looks pretty spectacular to visit if you're ever in the area.